I have had muscle pain side affects with the statin Zocor.

I stopped taking this drug after 4 months of use.

How long does this side affect last?

This is a very bad side effect of the statin meds. It can last for up to a month or more since you have been taking it for a while.

When you go back to the doc let him/her know that you are "sensitive" to statins. It doesn't mean that you have an allergy, you are just sensitive to statins.